• Puzzle

    Based on my N=1 survey and despite what it says below, I suspect this will actually be fairly easy even for some readers with advanced degrees. Still, I like this problem. To make it more interesting, see how many examples you need to deduce the algorithm.

    I grabbed this off Google+. For some reason, when I went back a second time (just moments later) to try to find who posted it, I couldn’t re-find it. So, apologies for not citing the source.


    Comments closed
    • Number of loops. Took me about five minutes to puzzle out.

    • 2

      Pre-school children cannot handle such mathematics. Therefore, it has to be in the design. When one looks at the design one can note the differences and isolate those numbers which always would be counted and see by how much.

      I bet that a lot of elementary school teachers will figure this problem out. I’ll bet that more mothers than fathers figure this out as well.

      • “I’ll bet that more mothers than fathers figure this out as well.”


        • Because mothers are more frequently involved with very young children and many teach them pattern recognition.

          Pattern recognition is also used by physicians and sometimes researchers. Anecdotal experiences frequently are pattern recognition (psychology not AI) and lead to disparities in health care that are frequently misunderstood by some researchers. That is one of the flaws of the Dartmouth Atlas and many others that are not careful in recognizing the incompleteness of their variables.

          We see this very frequently in the choice of an antibiotic. The antibiotic might work well all over the nation except in one area where for some reason there is resistance to the antibiotic. The smart physicians pick up a pattern of resistance early without proof and start using newer antibiotics before new guidelines are produced. Those physicians that recognize the leaders as more expert will follow suit.

          This puzzle teaches us some very important concepts that are missing in a lot of the medical literature. My initial answer to the puzzle was reflexive and **ALL** my responses are based upon considered thought and research that can be quite useful if taken in the fashion they are offered.

    • Wow that’s a great one. 0000 = 4 is the key…



      (As in, the answer — not how many examples I needed. That would be closer to “all of them”)

    • Took me under a minute, but it’s still a good one.

    • I didn’t get this. I puzzled over it for about 10 minutes, considering numbers in many different ways, including dates, times, zip codes, telephone numbers, telephone keypad letter mappings, odd and even, and various sequences of arithmetic operation. I even considered spatial rearrangements and inversions of the numbers, but just didn’t get around to counting loops.

      I figured the sequences of identical numbers were important clues, most coming out to zero, but three equalling 4. But it never occurred to my brain to consider the number shapes in and of themselves, prior to arriving at the numerical meaning of the shape.

      Deciding not to spend (waste) more time on it, I peeked at comments, and then engaged in facepalming.

      It seems the brain so habitually sees numbers as quantities, as the abstract concept they represent, that it can no longer see them as mere squiggly lines without great effort. A very interesting lesson.

      • I didn’t get it either. I tried a few things and realized that I wasn’t going to see the trick. As a programmer with advanced degrees (and Hacker’s Delight at the top of his Kindle stack), I knew from the hint that it was hopeless.

        I’d guess MDs would do better than nerds on this.

        Nice one, Austin!

    • 3-4 seconds.

      1 to deduce
      4 to confirm


    • The sad thing is I had the algorithm as 0,6,9=1, 8=2, everything else =0, but I didn’t even realize it was number of loops. I don’t think I can really count that as a win.

      • That is beautiful. It perfectly illustrates how from habit and experience the brain takes an unconscious pathway of translating symbol to meaning, completely factoring out particulars of the shapes of the symbols.

        I once had a conversation with an artist, when I, a science student, was taking an elective drawing class. She said that when you see as an artist you have to see things as they really look, not what they are used for. The artistic view must literally see shape, light, shadow, color, texture, etc. without regard to names, functions, and uses.

        The usual mode is to see the world in terms of utility. We don’t see how things look, we see them for what they do, what they can be used for, what their value is. We habitually take the details of appearance for granted, unless we make a conscious effort to break out of that habit.

    • The big hint is the pre-schooler who presumably couldn’t do any mathematical operations on the numbers.

    • I did it under ten minutes, but agreed it’s a great puzzle. The clue is in the pre-schooler comment and to avoid all calculation of the components.